1. Field of the Invention
This invention relates generally to viewing screen assemblies, and more particularly to a viewing screen assembly particularly adapted to be mounted on a helmet for visual communication in adverse environments.
2. Brief Description of the Prior Art
Heretofore, the most common underwater communication systems between an underwater diver and his helpers or supervisors topside have been audio communication systems. Traditionally, underwater divers dispatched to perform underwater tasks wear "hard hat" type helmets to protect themselves from injury underwater, to facilitate underwater audio communications, and to maintain comfort for long periods underwater. This type of communication has proven to facilitate increased safety and quality of work performed by divers than without it. More recently, scuba divers using self contained diving equipment with no direct link to the surface by means of an air hose, communications wire, or other line, have been offered FM wireless audio communications.
However, audio communications have some disadvantages. Helmeted divers have long depended upon visual inspections of the actual underwater conditions to determine the scope and methodology of the underwater tasks to be accomplished prior to going to work. Often, in discussions of the actual conditions with topside supervisors, the diver will be given a verbal explanation of the tasks to be accomplished while he is at the worksite underwater. Many times the diver does not get a clear understanding of what and how the topside personnel want him or her to do the task. This is due largely in part to the fact that the diver does not have direct visual contact with these personnel. If a diver is more than ten meters underwater and is required to come to the surface to look at blueprints or other visual information, he or she must go through a time consuming, decompression period in the water first. In some instances, a diver may desire to refer to blueprints, drawings, text, or other visual information during a dive, but because of time restraints, will complete the task at hand without viewing the proper reference materials.
Recent advancements in underwater audio communications have compounded this problem for scuba divers, because the scuba mode of diving is time limited, in that the scuba diver has a finite length of time to accomplish a task before running out of air. This is opposed to a helmeted diver's unlimited air supply which is delivered via an air hose from the surface.
In the past, the solution to this problem has been to make multiple dives, sometimes using two or more divers. The first diver inspects the job site, goes through the lengthy decompression process, then is brought to the surface. After a discussion with the topside engineers and diving supervisors, a second diver is dispatched to complete the task at hand. In circumstances where the diver found it necessary or advantageous to verify or consult plans, drawings, or to have a face to face discussion with topside personnel while at the work site, the diver would have to decompress and come to the surface first, or risk comprising his or her personal safety by attempting to complete the task without adequate planning. These methods suffer from inherent disadvantages. They are costly, time consuming, and may increase the risk of injury to the diver if not followed to the letter.
There is clearly a need in underwater diving for a means of communicating visual information to the diver while he or she is underwater to facilitate the diver's task accomplishment. Most advancements in underwater visual communication, such as television cameras, have focused on conveying an image of the underwater environment to the topside personnel, not in displaying an image of the topside environment to the diver. Divers who need to refer to information while underwater have not been considered in the evolvement of underwater visual information transmission.
Some development has been made in underwater structural inspection and testing using a hand-held television monitor (CRT) for ultrasonic non-destructive testing, such as disclosed by Sylvester, U.S. Pat. No. 4,102,203. In the Sylvester system, an ultrasonic transducer is held in one hand and a television monitor (CRT) which displays ultrasonic information is held in the other hand, and a television camera is mounted on the diver's helmet which allows topside personnel to see the diver's progress on the project.
Keeler, U.S. Pat. No. 5,091,778 discloses an imaging LIDAR system employing tunable and fixed frequency laser transmitters which enables a diver to see six to ten times further underwater than possible with the naked eye. However, the monitors used for this technology are too cumbersome and heavy to carry comfortably while swimming underwater.
Suggs, U.S. Pat. No. 5,079,753 discloses a sonar imaging system which uses sound waves and CRT (cathode ray tube) monitors to locate and display the position of a diver relative to submerged objects. An underwater sonar scanning head emits sound waves and projects an image of a top plan view of the area scanned to a monitor on the surface and to a monitor mounted on the side of the helmet of the diver. The sonar image produced on the helmet mounted monitor is viewed by the diver through a rectangular box-like "folding mirror or prism arrangement" which extends between the glass window of the helmet and the monitor. The diver's position and the position of the objects appear on the CRT screen as spots or "pips" in a field of concentric circles, similar to a radar screen. A station operator at the surface may place an X or other symbol on the pip representing the diver and the target object and produce a dashed line representing the path between them which appears on the diver's CRT screen to aid in guiding him toward the target.
Barr, U.S. Pat. No. 5,033,818 discloses an instrumentation box which is strapped to the diver's air tank and contains a timer and microprocessor that is connected to a pressure sensor in the diver's air hose for monitoring air tank pressure, depth and temperature, and elapsed time of the dive. The microprocessor is connected to a small display box mounted in the lower portion of the diver's face mask. The display box has a series of illuminated digits or symbols formed of LED's (light emitting diodes) or may comprise a LCD (liquid crystal display) illuminated by a separate light source. The digits or symbols are reflected upwardly onto an angled mirror at the top of the face mask which reflects them onto a partially reflecting mirror secured on the interior surface of the face plate. Barr merely functions as a self contained warning system wherein the diver enters dive parameters into the microprocessor and the sensors monitor these and other parameters and automatically flashes warnings through a system of mirrors if the pre-entered parameters are exceeded during a dive. The digits or symbols provide only numerical or symbolic images as to the status of the diver's air supply, water depth and elapsed time.
Heretofore, in non-fluid immersion applications, various helmet or head mounted display systems have been used. For example, there are military systems which assist pilots and combat troops in maneuvering aircraft and deploying weapons and aiming weapons without physical exposure to the enemy. These systems have also been used in night vision systems giving the user an advantage over an adversary who does not have the benefit of night vision equipment. Most of these types of systems have a sight reticle built into them and utilize a cathode ray tube (CRT) receiver or display rather than a flat panel display.
Burbo et al, U.S. Pat. No. 4,449,787 discloses a binocular imaging system for night vision which is inserted into a slot on the visor of a helmet that carries an image intensifier assembly having a first and second spaced apart tubular housing each of which contains a night vision optical system. This system has a pivot connection which allows the tubular housings to be locked in position away from the user's eyes or to be positioned in front of the user's eyes.
Copeland, U.S. Pat. No. 5,001,786 discloses a motorcycle helmet with a headlight mounted on it wherein a portion of the light from the headlight is diverted to illuminate a rotating translucent disk that gives directional heading information to the wearer.
Aileo, U.S. Pat. No. 4,231,117 discloses a helmet assembly having a rigid outer shell and an inner helmet assembly that fits closely over the wearers head which positions a portable cathode ray (CRT) display and reflector unit carried by the rigid outer shell of the helmet in a predetermined position relative to the eye of the wearer.
Hansen et al, U.S. Pat. Nos. 4,786,966 and 4,884,137 disclose a weapon mounted video camera which transmits video signals to a video display mounted on the helmet of the user using a non-visible light carrier wavelength which has a high degree of absorption in atmospheric water vapor. The image displayed is a holographic image, and in U.S. Pat. No. 4,884,137, the video display includes a sight reticle superimposed on the image of the target, so that the wearer can aim the weapon by moving it until the target object displayed by the camera is aligned with the sight reticle. This system depends upon line of sight.
In adverse non-fluid environments, such as space related environments, it is important for the technicians to have visual data available to them as a readily available reference when retrieving satellites, making repairs outside the space capsule, conducting experiments, and in building and assembling space stations and other structures in outer space. For example, in space station construction, the astronaut must have access to blueprints or other technical data while in an "extra vehicular activity" (EVA) mode, just as they would if they were doing construction on land. Astronauts are extensively trained for each specific task, and practice these tasks in simulated environments, such as water tank testing, and reduced atmosphere tanks. There is a need for a compact system for the transmission of general and technical information and the transmission of televised images to astronauts in adverse environments.
Holographic displays are commonly used in aircraft display systems. However, holographic displays suffer from the disadvantage of being viewed on a transparent background, which results in a lack of clear detail when the image is viewed while facing the sun or brightly lit objects. They also suffer from a limitation of being monochromatic, which when combined with a constantly changing background, in color and hue, makes holographic displays difficult to view when highly detailed information is presented via this format. This presents a problem when the holographic images are projected onto or through a transparent visor to be viewed while the viewer is also looking an object through the visor.
Withrington, U.S. Pat. No. 3,940,204 discloses a helmet mounted display utilizing a holographic lens with an abberated wavefront in conjunction with mirrors and prisms operating at a large off-axis angle to present a collimated virtual image of an object, such as the face of a cathode ray tube (CRT) to an observer.
A conventional space helmet developed by the National Aeronautics And Space Administration (NASA) has a thin layer of gold deposited on the outer visor for thermal radiation, which makes the interior of the helmet less transparent, but because of the lack of an atmosphere, and the extreme clarity in space, the brilliance of the lighting from the sun and other celestial bodies would be disconcerting and confusing when looking at projected images or holographic images in the space helmet. Thus, there is a need for an opaque display system suitable for use on space helmets.
Split screen images are of unrealized advantage and potential for use in adverse environments, such as underwater, outer space and smoke filled buildings. In the past, they have not been used in visual displays in helmets primarily because of size constraints of the display screens then in existence. The technology of miniaturization has only recently developed in the 1990's to the point where it was possible to produce a thin profile, solid state, lightweight, liquid crystal display screen (LCD) with a proportionally large viewing area. It is this type of screen which is incorporated in the present invention.
The present invention is distinguished over the prior art in general, and these patents in particular by a viewing screen apparatus for helmets or face masks of the type having a viewing area covered by a face plate which includes an enclosure adapted to be mounted on a helmet or face mask adjacent the face plate, a solid-state flat panel display screen and associated circuitry contained within the sealed enclosure for displaying visual images on the screen responsive to electronic signals, and a signal receiver connected with the screen for enabling the screen to receive electronic signals from an electronic signal transmission source. In one embodiment the enclosure is selectively movable between a viewing position adjacent the face plate and a position out of the wearer's field of vision to allow an unobstructed field of vision through the face plate. In another embodiment the apparatus includes an imaging device adapted to be connected to the helmet or face mask for transmitting electronic signals selected from the group consisting of analog, digital, television, and laser imaging signals to a remote location. The apparatus may be incorporated into various types of helmets and face masks such as underwater diver 's helmets and masks, space suit helmets, fire fighters helmets and masks, etc., and allows the wearer to view drawings, text and other information transmitted from a remote source while carrying out tasks in an adverse environment and also allows two way visual communication between two or more persons wearing helmets or masks equipped with the viewing system.